Bit ob drill stock



TED STATES PATENT EETCE.

DEXTER H. CHAMBERLAIN, OF BOSTON, MASSACHUSETTS.

BIT OR DRILL STOCK.

Specification of Letters Patent No. 9,353, dated October 26, 1852.

' panying drawings, letters, figures, and references thereof.

0f, the said drawings Figure 1 denotes a side view of my improved bit stock. Fig. 2 is a longitudinal section of it.

The bit stock on which my improvement is made is one wherein the bit is put in revolution by the hand of a person applied to a bell crank intervening between the handle and the bit. Such an instrument is well known and as improved by me is represented in the above mentioned drawings, A being the bell crank, B the handle, and C the part to which the bit or boring tool is affixed. The handle B turns freely in a shank or shaft D that extends into and through it.

To that part of the article to which the drill is usually fixed I apply a revolving shaft or drill holder E, such being supported in the same so as to be capable of a free revolution on its axis. This drill holder or shaft carries the drill F which may be affixed to it in any proper way.

A small pulley G is fixed on the shaft E and has an endless band H extended around it and another pulley I fixed in one end of a long shaft K that is made to run through the handle part a of the bell crank, and is supported therein and so as to be capable of being freely put in revolution on its axis. On the opposite end of the shaft K another pulley L is fixed, around which pulley L and a larger pulley M fixed firmly to the handle B a crossed endless belt or band N is carried. If t-he pulley M is made of a diameter larger than the pulley L it will be seen when the handle B is grasped firmly in the left hand of an operative and the bell crank seized in the right hand and turned around, that the shaft K will not only rotate around the axis of the shaft D, but will rotate on its own axis with an accelerated velocity and that the accelerated velocity will be imparted to the shaft E of the drill whereby the drill will be made to revolve several times during every or each revolution of the bell crank, whereas as a bell crank drill or bit stock is Acommonly made the bit or drill cannot move independently of the stock or crank but turns with it and only once during each ent-ire revolution of the crank.

Instead of the pulleys M and L and the endless band N two gear wheels may be substituted one being fixed to the handle in the place of the pulley M while the other is fixed on the shaft K and in the situation of the pulley L. So for the pulleys Gr, I, and the band H, three or any suitable number of gear wheels may be substituted whereby motion may be communicated from the shaft K to the shaft E.

My improved drill or bit stock is thus rendered much more effective in its operation than the ordinary bell crank bit stock above mentioned.

lfVhat I claim as my invention isrIhe improvement of combining with the bell crank A and handle B of the bit stock, the rotary bit holder or shaft E, the shaft K, the pulleys M, L, and endless band N (or two gears as stated) and the pulleys G, I, and band H, or gears, all substantially as described and for the purpose of accelerating the rotary motion of the drill beyond that of the bell crank when the instrument is used as stated.

In testimony whereof I have hereto set my signature, this twenty seventh day of September A. D. 1852.

DEXTER H. CHAMBERLAIN.

Witnesses:

R. H. EDDY, GEORGE W. CUTLER, 

